The Mousetrap (Plot Summary)

Plot Summary

Act One, Scene I

The play opens with a radio account of a woman murdered in London. Mollie and Giles have just opened a small guest house and inn with property that Mollie has inherited from her aunt. The action begins on their first day of business and with their first guests. Christopher Wren is the first guest to arrive. He is enthusiastic about the house and praises both the style and decor. Mrs. Boyle is the second guest to arrive, and she arrives complaining that a taxi did not meet her at the train (although she never provided an arrival time). The third guest to arrive, Major Metcalf, is carrying her luggage when he enters the hall a few moments later. Mrs. Boyle’s complaints about everything, including the lack of servants and experienced hosts, result in Giles offering to cancel her stay, but she declines and insists she will stay.

Miss Casewell arrives next with news that the snow is worse, and they are all likely to be snowed in for some days. She brings a newspaper account of the murder earlier that afternoon and joins with Wren and Giles in speculating about the murderer. There is a knock at the door and Mr. Paravicini arrives claiming to be stranded in the storm and seeking a room. Mr. Paravicini announces that the roads are so snowed in that that there will be no further arrivals or departures. His strange pronouncement that the inn is just “perfect” makes Mollie and Giles uneasy.

Act One, Scene II

This scene takes place the next afternoon. Mrs. Boyle is still complaining, but Major Metcalf is happy with the excellent breakfast and lunch and tells her so. Mrs. Boyle is writing a letter and Major Metcalf is reading when Wren enters and quickly exits again to seek quiet in the library. Soon after, Miss Casewell enters and turns the radio up loudly enough to force Mrs. Boyle out of the room. Wren again enters claiming to have fled Mrs. Boyle in the library. Wren and Miss Casewell talk, and she lets slip that she had a poor, deprived childhood too awful to think about.

The phone rings, and the local police superintendent claims he is sending a policeman over and that Giles should follow his orders. At the mention of the policeman, Miss Casewell flees the room clearly upset. Once again, Mrs. Boyle enters to complain about the heat, leading Giles to rush off and put more coal in the furnace. Mrs. Boyle tells Mollie that Wren’s story and name sound “fishy” and she thinks Mollie should check his references. Paravicini enters and warns Mollie that she should get references before she lets guests stay. He tells her that she can never tell who is a murderer, robber, madman, etc. At the same time he continues to leer suggestively at Mollie. Later, Mollie lets it slip about the police calling. At the news, Mrs. Boyle is disturbed; Metcalf is incredulous. Paravacini, who has been attending the fire, is startled enough to drop the poker.

Just then, Sgt. Trotter arrives on skis. Major Metcalf goes to use the phone and discovers that the line is dead. After his entrance, Trotter assembles everyone to tell them that he has been sent to provide police protection and alleges that someone present may be connected to the murder of a woman in London. The murdered woman was a local woman, who with her husband, was imprisoned for a number of years in connection to a child-neglect case. The woman and her husband were found guilty of actions that resulted in the death of one of the three children who had been mistreated while in their foster care. Clues left at the scene of the murder indicated that there may be two more possible victims. Trotter claims that the murderer may be one of the other two children who survived, a young man and woman — both in their twenties. Clues left at the scene have led Trotter to the guest house. Trotter asks everyone present if any of them have any connection to the child’s death so many years ago, but all present deny it. At that, Trotter goes off to search the house, and the guests begin to speculate about the murder and the possible identity of the murderer. Metcalf says that he knows that Mrs. Boyle was the magistrate who sent the children to live with those foster parents.

Sgt. Trotter returns from inspecting the house and states that he is going to phone his supervisor with a full report. When told that the phone lines are dead, Trotter remarks that they may have been cut. He sends Giles upstairs to check the other extension but not until he has mentioned that the killer may be among the guests. With everyone out of the room,

Trotter follows the telephone wire and crawls out the window searching for a cut end. Mrs. Boyle returns to the room and rushes over to close the open window. Just then, someone else enters the room. The lights are turned off and a scuffle and gurgles are heard. Mollie enters, turns on the light, and Mrs. Boyle’s body is seen on the floor.

Act Two

Trotter is interrogating all present. Everyone claims to have been alone; no one saw anyone else as they responded to Mollie’s cries for help. All their alibis sound slightly suspicious. Both Mollie and Giles are suspicious of one another because both hid the fact that they were in London the previous day. Trotter talks to Mollie alone and asks her about how well she knows her husband and about her knowledge of the abused children. Trotter tries to make Mollie think that Giles could be the surviving brother bent on revenge. But Mollie points out the murderer could even be the children’s natural father since no one has any idea of where he is and that Trotter could be looking for a middle-aged man and not a young man. After Trotter leaves the room, Wren enters quite distraught and convinced that Trotter will try to pin it all on him. He discloses that Wren is not his real name and that he is not an architect. Mollie tells Wren that she has an unhappy, even horrible, memory in her past, too, but does not disclose what it is. Giles enters and finds Wren comforting Mollie. He misunderstands and accuses Mollie of having had a longstanding affair with Wren. Mr. Paravicini enters as the Ralston’s are quarreling and announces that Trotter cannot find his skis. Everyone enters the room and all deny knowing anything about Trotter’s skis. Trotter resumes interrogating everyone about their knowledge of the murder or the child’s death years earlier.

Trotter speaks to everyone individually, and then tells them that he wants each one to reconstruct their actions during Mrs. Boyle’s murder, with one exception. Trotter wants each person to do what another claimed to be doing. Mollie is to play “Three Blind Mice” on the piano as Mr. Paravicini did during the murder. After a few moments Trotter calls Mollie back into the room. At first, Trotter accuses Mollie of withholding personal knowledge of the child’s murder. Trotter pulls a gun out of his pocket and reveals that he is Georgie, the dead child’s older brother. It was he who murdered the woman in London and Mrs. Boyle. Trotter drops the revolver and reaches out to strangle Mollie. He is interrupted by Miss Casewell, who tells him that she recognizes him as her brother Georgie. She leads him away telling him that she’s going to take him somewhere where he will get the kind of help he needs. Metcalf enters the room with the other guests and tells them that Georgie has been sedated. He explains that he knew that Georgie was not a policeman because he, Metcalf, was the policeman. Metcalf also divulges that Paravicini is a crook. And Mollie and Giles reveal that each was in London to buy an anniversary gift for the other. The play concludes with Mollie crying out that her pie is burnt.